[15:32] <cjwatson> jamesh,cristiangsp: I think the problem is that https://git.launchpad.net/gtk-common-themes/tree/snap/snapcraft.yaml says `architectures:\n  - all`, which doesn't seem to be valid according to https://forum.snapcraft.io/t/architectures/4972.  Example 6 there says (well, implies) that this is equivalent to `architectures:\n  - build-on: [all]\n    run-on: [all]`, but `all` is only valid in `run-on`
[15:34] <cjwatson> jamesh: Try `architectures:\n  - build-on: [amd64]\n    run-on: [all]` instead, if I understand what you're trying to do correctly?
[15:36] <cjwatson> jamesh: (You could probably actually use `build-on: [amd64, arm64, armhf, ppc64el, riscv64, s390x]`, and LP will pick its favourite.  I do think this is somewhat cumbersome, but LP doesn't own the file format here)